[ElementVisibilityObserver] Fix regression with default threshold

[ElementVisibilityObserver] Fix regression with default threshold

https://codereview.chromium.org/2830713003 (r468137,
913ee5fe4cfcc42ebc568965169258bc37fb0237) changed the default threshold
of ElementVisibilityObserver from std::numeric_limits<float>::min() to
zero, assuming that they would behave the same.

It turns out that there's some confusion here - see
https://github.com/WICG/IntersectionObserver/issues/164 - and for now
we should continue to use std::numeric_limits<float>::min() to
distinguish between completely hidden and partially visible.

BUG=726839
Review-Url: https://codereview.chromium.org/2919543002
Cr-Commit-Position: refs/heads/master@{#476265}
Committed: https://chromium.googlesource.com/chromium/src/+/945f4bf50cac68aee482fa5165c3a43379ed2241

[johnme, 2017-05-31 16:55:25]

johnme@chromium.org changed reviewers:
+ kinuko@chromium.org, mlamouri@chromium.org

[kinuko, 2017-05-31 23:13:40]

lgtm

https://codereview.chromium.org/2919543002/diff/1/third_party/WebKit/Source/c...
File third_party/WebKit/Source/core/dom/ElementVisibilityObserver.h (right):

https://codereview.chromium.org/2919543002/diff/1/third_party/WebKit/Source/c...
third_party/WebKit/Source/core/dom/ElementVisibilityObserver.h:39: void
Start(float threshold = std::numeric_limits<float>::min());
nit: Might be helpful to have a link to the discussion

[mlamouri (slow - plz ping), 2017-06-01 08:36:06]

lgtm

[johnme, 2017-06-01 11:35:22]

Addressed comment - thanks!

https://codereview.chromium.org/2919543002/diff/1/third_party/WebKit/Source/c...
File third_party/WebKit/Source/core/dom/ElementVisibilityObserver.h (right):

https://codereview.chromium.org/2919543002/diff/1/third_party/WebKit/Source/c...
third_party/WebKit/Source/core/dom/ElementVisibilityObserver.h:39: void
Start(float threshold = std::numeric_limits<float>::min());
On 2017/05/31 23:13:40, kinuko wrote:
> nit: Might be helpful to have a link to the discussion

Done.

[johnme, 2017-06-01 11:35:28]

The CQ bit was checked by johnme@chromium.org

[johnme, 2017-06-01 11:35:28]

The patchset sent to the CQ was uploaded after l-g-t-m from kinuko@chromium.org,
mlamouri@chromium.org
Link to the patchset: https://codereview.chromium.org/2919543002/#ps20001
(title: "Add link")

[commit-bot: I haz the power, 2017-06-01 11:35:43]

CQ is trying da patch.

Follow status at:
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-06-01 13:18:40]

CQ is committing da patch.

Bot data: {"patchset_id": 20001, "attempt_start_ts": 1496316928524560,
"parent_rev": "84ca44746a87520343acd76a40d51b948d9e56a8", "commit_rev":
"945f4bf50cac68aee482fa5165c3a43379ed2241"}

[commit-bot: I haz the power, 2017-06-01 13:18:49]

Description was changed from

==========
[ElementVisibilityObserver] Fix regression with default threshold

https://codereview.chromium.org/2830713003 (r468137,
913ee5fe4cfcc42ebc568965169258bc37fb0237) changed the default threshold
of ElementVisibilityObserver from std::numeric_limits<float>::min() to
zero, assuming that they would behave the same.

It turns out that there's some confusion here - see
https://github.com/WICG/IntersectionObserver/issues/164 - and for now
we should continue to use std::numeric_limits<float>::min() to
distinguish between completely hidden and partially visible.

BUG=726839
==========

to

==========
[ElementVisibilityObserver] Fix regression with default threshold

https://codereview.chromium.org/2830713003 (r468137,
913ee5fe4cfcc42ebc568965169258bc37fb0237) changed the default threshold
of ElementVisibilityObserver from std::numeric_limits<float>::min() to
zero, assuming that they would behave the same.

It turns out that there's some confusion here - see
https://github.com/WICG/IntersectionObserver/issues/164 - and for now
we should continue to use std::numeric_limits<float>::min() to
distinguish between completely hidden and partially visible.

BUG=726839

Review-Url: https://codereview.chromium.org/2919543002
Cr-Commit-Position: refs/heads/master@{#476265}
Committed:
https://chromium.googlesource.com/chromium/src/+/945f4bf50cac68aee482fa5165c3...
==========

[commit-bot: I haz the power, 2017-06-01 13:18:50]

Committed patchset #2 (id:20001) as
https://chromium.googlesource.com/chromium/src/+/945f4bf50cac68aee482fa5165c3...